There are various applications of flow restriction devices in the medical arts for closely regulating the flow of a fluid. One common use of such devices is with an infusion pump system wherein fluid medicine or other fluids are delivered to an injection site on the patient from the infusion pump. Embodiments are known wherein the flow restrictor is contained within the pump body. For example, U.S. Pat. No. 4,386,929 describes a short capillary tube contained within the pump housing for regulating the flow of dispensed medication. It is also known to include a flow restrictor downstream of the infusion pump, for example as with the delivery tube system described in U.S. Pat. No. 4,741,733.
U.S. Pat. No. 6,569,128 describes a catheter flow restriction system wherein a capillary-like restriction tube is contained within a catheter tube. The flow rate through the system is adjusted by trimming the length of the restriction tube and concentric catheter tube. The catheter can then be attached to an infusion device by a suitable connector, such as a Touhy-Borst connector.
Conventional flow restriction devices are, however, not without certain drawbacks, particularly the capillary tube restrictors. For example, such tube-type devices are relatively difficult and expensive to manufacture. Also, as requirements in the medical field tend towards decreased flow rates, it has become increasingly difficult to manufacture the tubes to achieve a specified flow rate due simply to machining tolerances and material limitations. For example, the smaller (in diameter) the tubes become, the more prone they become to particulate clogging.
A need thus exists in the medical field for a more reliable yet inexpensive flow restrictor that may be used in various systems, such as infusions systems and like devices.